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EFCI Southfield Mine - 2008 Annual Hydrology Report April 15, 2009 <br />2.0 GROUND WATER INFLOWS, WATER USE AND DISCHARGE <br />2.1 Mine Inflows <br />Mine inflow monitoring was discontinued after September 2001 immediately prior to the mine <br />portals being sealed in December 2001. Total mine inflows measured during 2001, as the last <br />reporting period, were estimated at 5.2 acre-feet as compared to 10.3 acre-feet during the 2000 <br />reporting period. Prior to 2001, mine inflow locations were monitored semi-annually during the <br />spring and fall for each annual reporting period. The 2001 mine inflows represented a decrease <br />from prior years possibly due to continuing drought conditions at that time along with the <br />elimination of former inflow or seep locations due to retreat mining Review of historic mine <br />inflow water quality monitoring results documented in previous AHR's indicates little variance in <br />inflow water quality over time. <br />2.2 Mine Water Handling, Consumptive Use, and Discharge <br />During active operations water-handling systems in the mine captured most mine water inflow near <br />their sources from where it was pumped downhill to the mined-out and abandoned west and north <br />areas of the mine. Mine water handling activities were discontinued after September 2001. Mine <br />inflows are anticipated to continue within the sealed mine workings and water will accumulate in <br />the lowest portions of the mined-out workings, gradually rising into other mined-out areas, until a <br />dynamic equilibrium is reached between mine water inflows and discharge to ground water <br />systems. <br />During the period of this report, consumptive water use was limited to minor pond evaporation. <br />Due to continuing drought conditions, only Ponds 4 and 5 at the Mine Site intermittently held water <br />from storm events during the summer months. The 2008 pond evaporation is estimated at 0.32 <br />acre-feet which is comparable to previous years. The source of water for any minor consumptive <br />uses typically is trucked to the site from Florence or Rockvale. No water was trucked to the site or <br />pumped from the Corley Well during 2008 and it is anticipated that future consumptive water use <br />will be limited to pond evaporation from the remaining four sedimentation ponds (Ponds 4, 5, L1, <br />and L2). Total consumptive use for 2008 is therefore estimated at 0.32 acre-feet, as indicated on <br />Table 1, Water Balance and Consumptive Use Summary. <br />The water balance shown on Table I compares water source withdrawals (consumptive use) with <br />discharge quantities. Withdrawals previously included any excess mine water pumped from the <br />mine as well as water withdrawn from wells. No water was pumped from the mine or withdrawn <br />from wells during 2008. Consumptive use during the reporting period was limited to only pond <br />evaporation. No pond water was discharged to area streams in 2008. The absence of discharges <br />was due to the combination of a low snowpack, infrequent storm events, and the reduced volume <br />of runoff from storm events as a result of increased vegetation establishment on reclaimed areas. <br />Previous pond discharges were consistently within NPDES permit limitations as documented in <br />prior Annual Hydrology Reports. <br />2008 AHR.doc WP Page 4